Bursting apparatus

ABSTRACT

A bursting apparatus is provided for separating and/or deleaving carbon paper from a multipart perforated continuous series of forms having carbon paper interleaved therein. The forms are fed to a bursting station which includes a clamp bar and a segmented bursting roller which is driven by a one-revolution clutch or the equivalent thereof. Each successive leading edge of the form actuates a stop-feed switch for automatically metering a single form length to the bursting station. The clutch is also actuated, thereby moving the clamp bar on the next succeeding form and the bursting roller revolves for one revolution to burst the leading form and deliver it to a deleaving station. The segmented burster roller has a slight helix on its engaging edge so that bursting tension will start at one edge and move progressively across the width of the form. The deleaving station has structure similar to that of the bursting station, but modified such that the clamping bar and bursting roller are positioned orthogonal to those in the bursting station and operate on the margin of the forms. When the leading edge of the form reaches stop fingers at the deleaving station, the clamp bar clamps one side margin of the form while the bursting roller revolves one revolution to separate the margin of the form to which the carbon paper is secured, thus deleaving the form. The bursting and deleaving operations are repetitive and continuous.

United States Patent 1 Hanson et al.

1 1 BURSTING APPARATUS [75] Inventors: Walter ,1. Hanson, Old Greenwich;

Erilts Parups, Norwalk, both of Conn.

[73] Assignee: Pitney-Bowes, 1nc., Stamford, Conn.

[22] Filed: Oct. 31, 1972 [21] Appl. No.2 302,607

Primary Examiner-Frank T. Yost Attorney, Agent, or FirmWilliam D.Soltow, Jr; Albert W. Scribner; Martin D. Wittstein [57] ABSTRACT Abursting apparatus is provided for separating and/or June 10, 1975deleaving carbon paper from a multipart perforated continuous series offorms having carbon paper interleaved therein. The forms are fed to abursting station which includes a clamp bar and a segmented burstingroller which is driven by a one-revolution clutch or the equivalentthereof. Each successive leading edge of the form actuates a stop-feedswitch for automatically metering a single form length to the burstingstation. The clutch is also actuated, thereby moving the clamp bar onthe next succeeding form and the bursting roller revolves for onerevolution to burst the leading form and deliver it to a deleavingstation. The segmented burster roller has a slight helix on its engagingedge so that bursting tension will start at one edge and moveprogressively across the width of the form. The deleaving station hasstructure similar to that of the bursting station, but modified suchthat the clamping bar and bursting roller are positioned orthogonal tothose in the bursting station and operate on the margin of the forms.When the leading edge of the form reaches stop fingers at the deleavingstation, the clamp bar clamps one side margin of the form while thebursting roller revolves one revolution to separate the margin of theform to which the carbon paper is scoured, thus deleaving the form. Thebursting and deleaving operations are repetitive and continuous.

5 Claims, 4 Drawing Figures BURSTING APPARATUS BACKGROUND OF THEINVENTION This invention relates to bursting apparatus and moreparticularly to the separation and/or carbon-paper deleaving of amultipart continuous series of forms having carbon paper interleavedtherein.

Computer-generated forms of a type conventionally delivered fromelectronic data processing systems consist of a multipart continuousseries of forms having carbon paper interleaved therein. Such forms areconventionally generated for use in billing and other typical businesstransactions. The continuous series of forms then requires furtherprocessing for end use such as mailing. This may require bursting orseparating the forms and removing the carbon paper therefrom, as well asthe performance of the end functions of stacking, stamping, sealing,inserting, collating (for additional enclosures) and folding. Theaforesaid end functions are all provided for with existing equipment inone continuous process. However, the bursting and carbon-paper deleavingfunctions are not so integrated and are currently accomplished usingseparate bulky and expensive equipment for performing the bursting anddeleaving operations. In current practice the first step in processingthe computer print-out forms, preparatory to mailing, is the removal ofthe interleaved carbon paper. This is typically done by first slittingthe margin to which the carbon paper is secured to provide manual accessto the carbon paper, then manually drawing the carbon paper over adeflector out at right angles to the path of the forms, and thensidewinding the carbon paper on a spooiing device; the forms restackingin a continuous fanfold. This step currently requires a separate pieceof equipment and an operator to place the forms in the equipment, windthe carbon paper on a roll to get it started, remove the stacked forms,and also remove from the roll the carbon paper deleaved from the forms.

The next step requires a separate piece of equipment for bursting thecontinuous series of forms into individual documents or forms whichinclude the original and One or more copies. This bursting step istypically accomplished by feeding the continuous forms at relativelyslow speed, deflecting the forms under a bursting knife, and thenengaging higher speed feed rollers. The speed differential tensions theforms and in conjunction with the knife bursts the forms along theperforation line between the forms. The individual forms are ejectedfrom the high-speed rollers to a stacker and then must be transported byan operator for further processing.

The separate steps of bursting and carbon-paper deleaving aretime-consuming and costly due to the requirement of individualequipments and operators time in performing the functions. This alsocuts down the number of forms which may be processed in a given timeinterval.

SUMMARY OF THE INVENTION Accordingly, it is an object of this inventionto provide a new and novel burster apparatus which can be used withpresent equipment to provide one continuous process for the handling andprocessing of computer form print-outs.

A further object of this invention is to provide a burster apparatuswhich increases the rate at which a continuous series of forms may betotally processed.

A still further object of this invention is to provide a burstingapparatus which integrates the steps of bursting and carbon-paperdeleaving from a multi-part continuous series of forms with existingequipment without requiring separate machines and operator time.

In carrying out this invention in one illustrative embodiment thereof abursting apparatus is provided for separating and/or deleaving carbonpaper from a multipart perforated continuous series of forms havinginterleaved carbon paper secured to one margin and free of the othermargin thereof. Controllable drive means are provided for advancing thecontinuous series of forms to a predetermined position where such drivemeans is disengaged. Overlying the forms in the predetermined positionare a clamping means and a segmented burster roller which is positionedover the leading edge of the continuous series of forms, with thesegmented portion overlying and out of contact with the leading edge ofthe series of forms in its inactivated position. Burster roller drivemeans are provided for rotating the burster roller one revolution whenactivated. When the predetermined position is reached by a form thedrive means is stopped, the clamping means clamps the next succeedingform of the series of forms along the perforation line between theforms, and the segmented burster roller is rotated for one revolutionbringing the burster roller in contact with the form thereunder therebytensioning and separating the form from the continuous series of forms.Carbon paper deleaving is accomplished in the same manner except thatthe clamping means and burster roller are positioned over the perforatedmargins of the forms on which they operate, to provide the carbon-paperdeleaving function. The bursting and carbon-paper deleaving functionsmay be performed either singly or in combination, the latter being thepreferred form, in order to obtain maximum advantage of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows one type of form, partlybroken away to illustrate its multiple part construction, which isdesired to be processed by the present invention.

FIG. 2 is a conceptual isometric view of bursting apparatus forperforming the bursting function in accordance with this invention.

FIG. 3 is a conceptual isometric view of bursting apparatus forperforming the carbon-paper deleaving function in accordance with thepresent invention.

FIG. 4 is an isometric view of one form of the bursting apparatus ofthis invention incorporating both the bursting and carbon deleavingfunctions operating on a continuous series of multipart forms.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. I, thereis shown a multipart continuous series of forms 10 of a type deliveredfrom electronic data processing systems which are to be furtherprocessed for ultimate use, such as mailing. The forms 10 are continuouswith the first form in the series, illustrated as form I4, succeeded bythe next succeeding form 12, which forms are delineated by a perforationline 13 therebetween. The forms I0 are multipart forms having anoriginal 15 and one or more copies l7 and 19, which are separated by oneor more car bon papers 16 and 18. Both the right-hand and left handmargins 22 and 24 respectively are bonded, with the carbon paper 16 and18 being secured to the righthand margin 22 at the edge 20 and theleft-hand edge of the carbon paper being free. Both margins 22 and 24contain standard sprocket holes 26 therein with a conventional half-inchpitch. The first form 14 of the continuous series of forms 10 has aleading edge 11. The series of forms 10 is illustrated as being typicalof the type of forms of the same general type having either more orfewer copies and more or fewer carbons may be utilized.

in processing the forms such as shown in FIG. 1, it is generallyrequired that the forms be separated, or bursted. into individual formsand the conceptual illustration of FIG. 2 is utilized to explain thisfunction in accordance with the present invention. The continuous seriesof forms 10 are fed to a bursting station generally identified with thereference character 25. The forms are fed to station 25 by sprocketwheels 28 until the leading edge 11 of the first form 14 reaches apredetermined position or feed stop-line. The bursting station 25 has anupper clamp bar 30 and a lower clamp bar 31 which are open when theforms 10 are being fed to the station 25 and are Closed for performingthe bursting function. The lower clamping bar 31 may be in the form of astationary table or platform forming part of the station. The clampingbars are adjustable in the direction of form travel so that differentlength forms can be accommodated. On the forward end of the burstingstation 25 are positioned cooperating bursting rollers 36 and 34. Theupper bursting roller 36 is segmented, having a flat portion 38 thereonand a leading bursting edge 40 which is formed with a slight helix. inopera tion to provide the bursting function, the sprocket wheels 28advance the leading form 14 of the continuous series of forms 10 untilthe leading edge 11 of the first form 14 reaches the predetermined feedstop-line, at which point the movement of the sprocket wheels 28 isstopped by suitable arrangement, such as disengagement of a clutch, thusproviding the function of automatically metering a one-form length tothe bursting station. The clamp bars 30 and 31 then effectively closeengaging the next succeeding form 12. The bursting rollers then rotatethrough one revolution with the leading edge 40 of the burster rollercontacting the form 14 and applying bursting tension progressivelyacross the width of the form 14. The rollers 36 and 34 eject the burstedform 14 so that the latter may be transported or stacked for asucceeding processing ste 'l he carbon-paper deleaving function will,for ease of explanation and understanding, be initially discussed inconnection with the conceptual showing of FIG. 3. The bursted individualform 14 is transported or fed to a deleaving station generally referredto by reference char acter 45. The deleaving station has a pair of sideclamp bars 44 and 46 and a pair of side-bursting rollers 50 and 48. Theupper side-bursting roller 50 is segmented and constructed in the samemanner as bursting roller 36 at the bursting station 25. It will benoted that the bursting station 45 has essentially the same elements asthe bursting station 25, except that the clamp bars 44 and 46 and therollers and 48 of the deleaving station 45 are orthogonal or disposed atsubstantially at right an gles with respect to their counterparts in thebursting tatiou af', wit on tic. .atio. working on the nmrg ns the of tintent instead of i tl i. 1 t i i st ing station i?- i= Q J' 14 facedovvn so that the upper burster re 1 50 oper ates on the right-handmargin of the fr rrn shown in FIG. 1. it will be remembered that therighthand margin of the form 14 is the one to which the ca n paper isaffixed, with the carbon paper being free at the left hand margin. Withthe form 14 in positirn'. and clamped the burster roller 50 has itsleading hencal edge con tacting the right-hand margin 22 of the form,bursting it along the length thercofon perforations ii. A pair ortakeaway rollers 52 are provided for transpoi ing the separated margin22 with the attached 6. LIVCCl LZilbt'in paper to a suitable disposalbin. l. should .11 noted thn; the deleaving station 45 has similarcomptments and operates essentially the same as the bursting station 25with the difference being that deleaving station is a side-burstingopcrznion which is perfo med on a different portion of the form 14.

An impicmcnta on of the vombined bursting and carbon-paper de eavingfunctions is shown In FIG. 4. Like reference nurnerals from previousfigures are used where appncable. llrive for the apparatus is providedby a motor 82 which powers :1 chain-driven drive 84 operating onsprocket wheei drive shaft 88 and drive shaft 86. Drive shaft 86 aisdrives a deleaving station drive-shaft 95 through licvci gears 97. Thecontinuous series of forms 10 are f d via sprocket wheels 28 to theburster station 25. The forms of FIG. l are fed face down in thisoperation to implement the bursting operation in the form illustrated inFIG. 4. The drive for the sprocket wheels 28 is provided by the driveshaft 88 operating through a wrap spring type clutch having anassociated control solenoid 92. The bursting station 25 is provided witha stop finger switch 72 which is contacted and deflected by the leadingedge of the next succeeding form, which in this case is form 12, at itsleading edge 13. The clamping bar 30 is provided to grip the leadingedge of the next succeeding form in co operation with a lower clampingmeans which is not shown in FIG. 4 but which may be in the form ofatable or platform over the forms 10- move. The upper segmented burstingroller 36 and lower bursting roller 34 are provided with intermeshinggears at the far end (not shown for ease of illustration) so that theyrotate in unison when driven by shaft 60. The drive shaft 86 haspositioned thereon any suitable type halfrevolution clutch 52 having aclutch latch 54 cooperat ing therewith which is controlled by a solenoid56. The half-revolution clutch 52 is geared as at 58 to the bursterroller shaft 60 on which is secured l) a timing cam 62 which cooperateswith timing switch 64, and (2) a stepping cam 66 which actuates afour-bar link age 68 for operating a springdoaded clamp bar shaft 76secured to the pivotable clamping bar 30.

The deleaving station 45 is provided with any suitable continuouslymoving transport means, such as belts 74 that are driven by the driveshaft 86 and associated pulleys, for moving separated documents from thebursting station 25 into position in the deleaving station 45.

A switch 80 is provided which is adapted to be actuated by the leadingedge of a document that is fed into operative position in station 45',the document being held in this position in the bursting station 45 bymovable stop fingers 78 that hold the document in opposition to thecontinuous frictional drive action of belts 74. Fingers 78 are coupledby mechanical linkage 94 to clutch latch clamping The upper segmentedburster roller 50 is adapted to be driven by a side burster roller shaft93 which is coupled via gear 97a to a half-revolution clutch 100. A stepcam 98 is mounted on said shaft 93 for actuating a four-bar mechanicallinkage 96 for controlling the clamp bar 44. The operation of the drivemeans for the clamp bar 44 and the roller 50 corresponding to thosedescribed above for bar 30 and roll 36. The associated lower burstingroller, as well as the ejection rollers for laterally feeding thedeleaved carbon paper, are not shown in FIG. 4 for ease of illustration,but respectively correspond to those shown at 48 and 52 of FIG. 3. Thelower clamping bar which is also not shown, may be in the form of aplatform underlying the station over which the belts 74 and thedocuments traverse. It will be noted that the form clamping means,bursting rollers, and the actuating means therefor respectively, at thedeleaving station 45 are similar to those respectively disposed at thefirst bursting station 25. The electrical circuit interconnecting thevarious switches and solenoids of P10. 4 may be of any conventionaldesign to produce the control sequencing hereinafter described and henceneed not be further shown or described herein.

The operation of the apparatus of FIG. 4 will now be described assumingthat the first form 14 has already been separated and is to be fed intothe deleaving station 45 while the next form 12 is fed into the burstingstation 25.

When a start-feed signal is applied to the solenoid 92 the clutch 90 isengaged and the sprocket wheels 28 ad vance the forms into the burstingstation 25. The form shown in position in the bursting station 25 ofFIG. 4, is form 12, and it is advanced until the front edge 13 thereofmakes contact with the burster control switch 72. (It should be notedthat switches 72 and 80 are electrically switched when the switch armsthereof ride up and over the leading edges of the associated advancingforms, as illustrated in FIG. 4). Operation of switch 72 serves tode-energize the solenoid 92, disengaging the clutch 90 and stopping thesprocket wheels 28. Thus one document or form length is automaticallymetered into the bursting station 25 and the form 12 stops in a positionto be bursted on demand. A machine cycle switch (not shown) actuatessolenoid 56 to momentarily release the clutch latch 54 so that bursterdrive shaft 60 is driven through one revolution. in the implementationshown the conventional type clutch 52 is a halfrevolution clutch coupledthrough gear 58 so as to produce one full revolution of the burstershaft 60; this of course constituting the equivalent of one-revolutionclutch. This single counterclockwise revolution of shaft 60 will causethe clamping means 71 to clamp the next strip form, and then thebursting rollers 34, 36 to separate the form 12 from the trailing forms.To this end when counterclockwise rotation of cam 66 is initiated fromthe position shown in FIG. 4, the pivoted cam follower portion 68b ofsaid linkage 68 will drop off the outermost cam surface so as toeffectively allow said four bar linkage portion 68a to swing upwardlysufficiently to permit the spring biased arm 69 secured to mountingshaft for bar 30 to rotate in a counterclockwise direction. This springdriving action will cause the lobe 71 of the clamp bar 30 to swingdownwardly into clamping engagement with the forward end portion of theform 12a next following form 12 to hold said following form immobile.During this clamping action the bursting rollers 36 and 34 will berotated through one revolution by the burster shaft 60, bringing thehelical edge 40 of the burster roller 36 in contact with the leadingedge of the form 12 for providing a bursting tension which starts at oneedge and moves progressively across the width of the form 12, separatingit from the continuous series of forms 10. After the step cam 66 hasrevolved about 180, the four bar linkage portion 68a will be loweredsufficiently to pivot the arm 69 clockwise against its said biasedaction thereby raising the clamp bar lobe 71. The switch 64 which isoperated by timing cam 62 when the clamp bar lobe 71 is raised serves toactuate said solenoid 92, and thus the clutch 90, so as to start thesprocket wheel feed to meter the next document 12a into the burstingstation 25.

During the above described operations on form 12 at station 25, thebursted form 14 which had earlier been separated from the continuousseries of forms 10 at said station 25 is transported via friction belts74 to the deleaving station 45. The separated document 14 moves into thedeleaving station 45 until its leading edge 11 contacts the side bursterswitch 80, and is held in position by the now elevated fingers 78. Theside burster control switch actuates solenoid 104 to remove the clutchlatch 102 from the conventional type half-revolution clutch 100.Operation of clutch causes (1 step cam 98 to actuate the four-barlinkage 96 so that the lobe 47 of clamp bar 44 is brought down insidethe left-hand margin 24 of the document 14; this action being similar tothat for the said clamping movement of lobe 71 on clamp bar 30, and (2)the burster roller shaft 93 to then be driven through one revolution viathe gear 97a. This clamping of the form margin 24 and the rotation ofthe burster roller 50 through one revolution causes separation (alongscore line 21) of the margin 21 together with the attached carbon papersfrom the rest of the form 14. A switch 960 actuated by a cam 99 securedto the deleaving station drive shaft 93 operates the solenoid 104 priorto the completion of one revolution of the side burster roller driveshaft 93 so as to insure only a single cycle of operation of thehalf-revolution clutch 100 and allowing a set of continuously driventake away rolls, such as those illustrated at 52 of FIG. 3, to laterallyremove the form margin 22 and the attached carbon sheets from thedeleaving station 45 and deliver such to a suitable waste bin.

Pressure rollers 76 are provided at the deleaving station which overlaythe forms so that the latter may be urged against and fed by thecontinuously driven friction belts 74 towards the stop fingers 78. Theform 14 is held in the burster station 45 until said stop fingers 78 arelowered at which time the belts 74 advance the separated forms withoutthe carbon interleafs downstream, as indicated by arrow 105, forsubsequent stacking or the performing of the next operation on theforms. The stop fingers 78 are cyclically lowered by linkage 94 eachtime the solenoid 56 for the burster drive clutch for station 25 isactuated.

The stations 25 and 45 can be adjusted to accommo date documents ofdifferent lengths by varying the relative position of the clamp 30, 31with respect to the burster rollers 36 and 34. Likewise the position ofclamp 44, 46 with respect to roller 50 may be made adjustable toaccommodate documents of different widths; the four bar linkages 68 and96 still swing to control the associated clamp means 7i and 47 in any ofsuch adjusted positions.

The burster apparatus of the present invention can be attached directlyto conventional downstream folding, inserting. mailing and/or otherdocument processing machines. When so used the forms may thus becompletely machine processed in a continuous line operation fromcomputer print-out to mailing. When per forming both the bursting anddeleaving operations using applicant's invention the usual separate,bulky and expensive machines for performing these functions areeliminated, thus form processing is speeded up and costly manual laboroperations are practically eliminated.

Since other modifications and changes varied to fit particular operatingrequirements and environments will be apparent to those skilled in theart, the invention is not considered limited to the examples chosen forpurposes of disclosure. and covers all changes and modifications whichdo not constitute departures from the true spirit and scope of thisinvention.

What is claimed is:

l. A bursting apparatus for separating a continuous series of formshaving perforation lines therebetween into individual forms: comprisingA. feed means for intermittently advancing said continuous series offorms;

B. clamping means having a clamping condition for holding saidcontinuous series of forms immobile and a release condition for allowingfeed movement of said continuous series of forms;

C. actuating means for said clamping means;

D. burster roller means adapted when operated to apply a feed tensionforce to the leading form in said series of forms;

E. drive means for rotating said burster roller means;

and

F. control means for controlling the operation of said clamp actuatingmeans and said burster roller drive means to cause said burster rollermeans to apply a tension feed force to the leading form in said serieswhile said clamping means is clamping the next form following said leadform in said series whereby said lead form may be separated from theremaining forms in said series;

Gr said actuating means for said clamping means including a movable barmember and means for moving said bar between clamping and releasepositions, said bar member having an operative longitudinal edge thatserves to operate said clamping means for any form length adjustedposition of said clamping means along the length of said bar member.

2. A bursting apparatus for separating a continuous series of formshaving perforation lines therebetween into individual forms; comprisingA. feed means for intermittently advancing said con tinuous series offorms so that the leading edge of the series is moved to a predeterminedposition;

B. clamping means having a clamping condition for holding saidcontinuous series of forms immobile and a release condition for allowingfeed movement of said continuous series of forms;

C. actuating means for said clamping means;

D. burster roller means positioned adjacent the leading edge of saidcontinuous series of forms when the latter is in said position, andadapted when operated to apply a feed tension force to the leading formin said series of forms;

E. driving means for rotating said burster roller means; and

F. control means for controlling the operation of said clampingactuating means and said burster roller drive means to causesaid bursterroller means to apply a tension feed force to the leading form in saidseries while said clamping means is clamping the next form followingsaid lead form in said series whereby said lead form may be separatedfrom the remaining forms in said series;

0. said control including a switch means that is operative to cause saidfeed means to be disabled when said leading edge of said series of formsreaches said predetermined position.

3. The bursting apparatus set forth in claim 2, wherein said controlmeans includes clutch means acti vated by said switch means for drivingsaid burster roller drive means for one revolution, said burster rollerdrive means including means for actuating said clamping means prior tothe bursting action and then releasing said clamping means.

4. The bursting apparatus set forth in claim 3 wherein said clampingmeans includes a rotatably mounted bar having a radially extendingclamping portion that is adapted to be swung into and out of clampingcontact with said forms.

5. The bursting apparatus set forth in claim 3, wherein said means foractivating and releasing said clamping means comprises a step cammounted on said burster roller drive means which drives a mechanicallinkage coupled to said clamp means.

1. A bursting apparatus for separating a continuous series of formshaving perforation lines therebetween into individual forms: comprisingA. feed means for intermittently advancing said continuous series offorms; B. clamping means having a clamping condition for holding saidcontinuous series of forms immobile and a release condition for allowingfeed movement of said continuous series of forms; C. actuating means forsaid clamping means; D. burster roller means adapted when operated toapply a feed tension force to the leading form in said series of forms;E. drive means for rotating said burster roller means; and F. controlmeans for controlling the operation of said clamp actuating means andsaid burster roller drive means to cause said burster roller means toapply a tension feed force to the leading form in said series while saidclamping means is clamping the next form following said lead form insaid series whereby said lead form may be separated from the remainingforms in said series; G. said actuating means for said clamping meansincluding a movable bar member and means for moving said bar betweenclamping and release positions, said bar member having an operativelongitudinal edge that serves to operate said clamping means for anyform length adjusted position of said clamping means along the length ofsaid bar member.
 2. A bursting apparatus for separating a continuousseries of forms having perforation lines therebetween into individualforms: comprising A. feed means for intermittently advancing saidcontinuous series of forms so that the leading edge of the series ismoved to a predetermined position; B. clamping means having a clampingcondition for holding said continuous series of forms immobile and arelease condition for allowing feed movement of said continuous seriesof forms; C. actuating means for said clamping means; D. burster rollermeans positioned adjacent the leading edge of said continuous series offorms when the latter is in said position, and adapted when operated toapply a feed tension force to the leading form in said series of forms;E. driving means for rotating said burster roller means; and F. controlmeans for controlling the operation of said clamping actuating means andsaid burster roller drive means to cause said burster roller means toapply a tension feed force to the leading form in said series while saidclamping means is clamping the next form following said lead form insaid series whereby said lead form may be separated from the remainingforms in said series; G. said control including a switch means that isoperative to cause said feed means to be disabled when said leading edgeof said series of forms reaches said predetermined position.
 3. Thebursting apparatus set forth in claim 2, wherein said control meansincludes clutch means activated by said switch means for driving saidburster roller drive means for one revolution, said burster roller drivemeans including means for actuating said clamping means prior to thebursting action and then releasing said clamping means.
 4. The burstingapparatus set forth in claim 3 wherein said clamping means includes arotatably mounted bar having a radially extending clamping portion thatis adapted to be swung into and out of clamping contact with said forms.5. The bursting apparatus set forth in claim 3, wherein said means foractivating and releasing said clamping means comprises a step cammounted on said burster roller drive means which drives a mechanicallinkage coupled to said clamp means.